As a brand new human-computer interaction device, a touch screen improves efficiency and convenience of man-machine dialogue to a large extent, and can allow entertainment and official business to become more lively and relaxed, due to characteristics such as directness, high efficiency, accuracy, smoothness, and fashion. The touch screen can be divided into a resistive type, a capacitive type, an infrared optical type and other types. Typically, the touch screen of the capacitive type includes a touch screen of a self-capacitive type and a touch screen of a mutual-capacitive type.
The touch screen of the self-capacitive type includes a touch electrode array made from a transparent conductive material (e.g., Indium Tin Oxide (ITO)) on a base substrate, and these touch electrodes respectively constitute capacitors with ground. When a finger touches the touch screen of the self-capacitive type, capacitance of the finger will be superimposed on a corresponding touch electrode, and a touch detection chip may determine a touch position in a touch period by detecting change of capacitance values of the respective touch electrodes. The touch screen of the mutual-capacitive type includes a lateral electrode and a longitudinal electrode made from the transparent conductive material (e.g., Indium Tin Oxide (ITO)) on the base substrate, and capacitance will be formed in a position where the two sets of electrodes intersect with each other. When the finger touches a capacitive screen, coupling between two electrodes near a touch point is affected, so that capacitance between the two electrodes is changed. The touch detection chip determines the touch position in the touch period by detecting such a change of the capacitance value.
On the other hand, with development of smart technology, a wearable smart device is more and more favored by consumers. These smart devices, in addition to characteristics such as portability, fashion, and intellectualization, almost all need a touch performance. However, shapes of touch screens of these smart devices are not rigidly limited to a general rectangle, but a variety of shapes such as a circle and an octagon can be adopted, so as to meet a user's demands on fashion and aesthetics. However, because its touch screen is non-rectangular (heteromorphic), a touch electrode structure originally used in a rectangular device is no longer applicable. The original touch electrode structure continues to be used on the heteromorphic touch panel, and all sorts of problems may be encountered, for example, an edge of the touch panel or the touch electrode at the corner is not completely or evenly covered, resulting in defects such as inaccurate reporting points, or poor linearity.